using System; 
using System.Collections.ObjectModel;
using System.Text;

namespace System.Data.Linq.SqlClient { 

    /// <summary> 
    /// Methods for checking whethe a query was compatible with the 
    /// server it will be sent to.
    /// </summary> 
    static internal class SqlServerCompatibilityCheck {

        /// <summary>
        /// Private visitor class checks each node for compatibility annotations. 
        /// </summary>
        private class Visitor : SqlVisitor { 
 
            private SqlProvider.ProviderMode provider;
            internal SqlNodeAnnotations annotations; 

            internal Visitor(SqlProvider.ProviderMode provider) {
                this.provider = provider;
            } 

            /// <summary> 
            /// The reasons why this query is not 2K compatible. 
            /// </summary>
            internal Collection<string> reasons = new Collection<string>(); 

            internal override SqlNode Visit(SqlNode node) {
                if (annotations.NodeIsAnnotated(node)) {
                    foreach (SqlNodeAnnotation annotation in annotations.Get(node)) { 
                        SqlServerCompatibilityAnnotation ssca = annotation as SqlServerCompatibilityAnnotation;
                        if (ssca != null && ssca.AppliesTo(provider)) { 
                            reasons.Add(annotation.Message); 
                        }
                    } 
                }
                return base.Visit(node);
            }
        } 

        /// <summary> 
        /// Checks whether the given node is supported on the given server. 
        /// </summary>
        internal static void ThrowIfUnsupported(SqlNode node, SqlNodeAnnotations annotations, SqlProvider.ProviderMode provider) { 
            // Check to see whether there's at least one SqlServerCompatibilityAnnotation.
            if (annotations.HasAnnotationType(typeof(SqlServerCompatibilityAnnotation))) {
                Visitor visitor = new Visitor(provider);
                visitor.annotations = annotations; 
                visitor.Visit(node);
 
                // If any messages were recorded, then throw an exception. 
                if (visitor.reasons.Count > 0) {
                    throw Error.ExpressionNotSupportedForSqlServerVersion(visitor.reasons); 
                }
            }
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.